Magnetic writer having an asymmetric gap and shields

ABSTRACT

A method and system provide a magnetic transducer. An intermediate layer including multiple sublayers is provided. A trench is formed in the intermediate layer. A main pole having a bottom, a top wider than the bottom, a first side and a second side opposite to the first side is provided in the trench. An asymmetric gap is provided along the first and second sides of the main pole. The asymmetric gap terminates closer to the top of the main pole along the first side than on the second side. The asymmetric gap has a first thickness along the first side and a second thickness different from the first thickness along the second side. An asymmetric shield is provided on the asymmetric gap. The asymmetric shield includes a half side shield having a bottom between the top and the bottom of the main pole and terminating on the asymmetric gap.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of U.S. application Ser.No. 14/289,345, filed May 28, 2014, entitled “METHOD FOR FABRICATING AMAGNETIC WRITER HAVING AN ASYMMETRIC GAP AND SHIELDS” now U.S. Pat No.9,153,255 B1 issued on Oct. 6, 2015, which claims priority toprovisional U.S. Patent Application Ser. No. 61/948,417, filed on Mar.5, 2014, which is hereby incorporated by reference in its entirety.

BACKGROUND

FIG. 1 depicts an air-bearing surface (ABS) view of a conventionalmagnetic recording transducer 10. The magnetic recording transducer 10may be a perpendicular magnetic recording (PMR) head. The conventionaltransducer 10 includes an underlayer 12, side gap 14, side shields 16,top gap 17, optional top, or trailing, shield 18 and main pole 20.

The main pole 20 resides on an underlayer 12 and includes sidewalls 22and 24. The sidewalls 22 and 24 of the conventional main pole 20 form anangle with the down track direction at the ABS. The side shields 16 areseparated from the main pole 20 by a side gap 14. The side shields 16extend at least from the top of the main pole 20 to the bottom of themain pole 20. The side shields 16 also extend a distance back from theABS. The gap 14 between the side shields 16 and the main pole 20 mayhave a substantially constant thickness. Thus, the side shields 16 areconformal with the main pole 20.

Although the conventional magnetic recording head 10 functions, thereare drawbacks. In particular, the conventional magnetic recording head10 may not perform sufficiently at higher recording densities. Forexample, at higher recording densities, a shingle recording scheme maybe desired to be sued. In shingle recording, successive tracks partiallyoverwrite previously written tracks in one direction only. Part of theoverwritten tracks, such as their edges, are preserved as the recordeddata. In shingle recording, the size of the main pole 20 may beincreased for a given track size. However, in order to mitigate issuessuch as track edge curvature, shingle writers have very narrow side gaps14. Other design requirements may also be present. The magnetictransducer 10 may not perform as desired or meet the design requirementsfor such recording schemes. Without such recording schemes, theconventional transducer 10 may not adequately perform at higher arealdensities. Accordingly, what is needed is a system and method forimproving the performance of a magnetic recording head.

BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 depicts an ABS view of a conventional magnetic recording head.

FIG. 2 depicts a flow chart of an exemplary embodiment of a method forproviding a magnetic recording transducer having an asymmetric gap andasymmetric shields.

FIGS. 3A, 3B and 3C depict side, ABS and apex views of an exemplaryembodiment of a magnetic recording disk drive having an asymmetric gapand asymmetric shields.

FIG. 4 depicts a flow chart of another exemplary embodiment of a methodfor providing an asymmetric side gap.

FIG. 5 depicts an ABS view of another exemplary embodiment of a magneticrecording transducer.

FIG. 6 depicts a flow chart of another exemplary embodiment of a methodfor providing a magnetic recording transducer having an asymmetric gapand asymmetric shields.

FIGS. 7 through 21 depict ABS views of an exemplary embodiment of amagnetic recording transducer fabricated using the method.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 2 depicts an exemplary embodiment of a method 100 for providing amagnetic recording transducer. For simplicity, some steps may beomitted, interleaved, combined and/or performed in another order. Themethod 100 is described in the context of providing a magnetic recordingdisk drive and transducer 200. However, the method 100 may be used tofabricate multiple magnetic recording transducers at substantially thesame time. The method 100 is also described in the context of particularlayers. A particular layer may include multiple materials and/ormultiple sub-layers. The method 100 also may start after formation ofother portions of the magnetic recording head. For example, the method100 may start after a read transducer, return pole/shield and/or otherstructure have been fabricated.

An intermediate layer including at least multiple sublayers is provided,via step 102. In at least the region in which the pole tip and sideshields are to be formed (shield region), the intermediate layerincludes a first sublayer, a second sublayer and at least one etch stoplayer between the first and second sublayers. In some embodiments, thefirst and second sublayers include the same material, such as aluminumoxide or silicon oxide. In other embodiments, the first and secondsublayers may include different material(s). The etch stop layer isresistance to an etch (such as a wet etch) of the second sublayer. Insome embodiments, for example, the etch stop layer may include siliconnitride and/or silicon oxide. The etch stop layer may also be thin. Forexample, the etch stop layer may be 8-12 nm thick. In some embodiments,step 102 includes full-film depositing a first layer, full filmdepositing an etch stop layer and full film depositing a second layer.In an embodiment, the portions of these layers outside of the sideshield region and pole tip region may be removed. The first and secondsublayers and etch stop layer may thus remain in the side shield region.The third sublayer may then be deposited and the layer(s) planarized.Thus, the intermediate layer may be formed.

A trench is formed in an intermediate layer using one or more etches,via step 104. The trench formed has the desired geometry and locationfor formation of the main pole. For example, the top of the trench maybe wider than the bottom so that the top of the main pole may be widerthan the bottom. The trench extends at least partially into the firstsublayer in the shield region. In some embodiments, some or all of thetrench may extend through the first sublayer. However, if a leading edgebevel is desired, the bottom of the trench may slope in the down trackdirection. In such embodiments, the portion of the trench at the ABS maynot extend through the first sublayer. However, apertures that are theupper portions of the trench are generally formed in the second sublayerand etch stop layer.

The main pole is provided in the trench, via step 106. In someembodiments, step 106 includes depositing a seed layer, such as Ruand/or magnetic seed layer(s). High saturation magnetization magneticmaterial(s) are also provided. For example, such magnetic materials maybe plated and/or vacuum deposited. The material(s) may be planarized.Further, a trailing bevel may be formed in the main pole. Formation ofthe trailing bevel may include covering a portion of the main polerecessed from the ABS and then ion milling the main pole at an anglefrom the down track direction. This step may be performed afterformation of the side shields. The pole formed in step 106 may beconformal to the trench, nonconformal with the trench, or include bothconformal and nonconformal portions.

An asymmetric gap is provided, via step 108. The asymmetric gapterminates at different distances from the top of the pole on the sidesof the main pole. In addition, the gap may be thicker on one side of thepole than on the other side of the main pole. Formation of the gap instep 108 may include covering the pole and the intermediate layer on oneside of the main pole. The second sublayer is removed on the exposedside of the main pole in the side shield region. Thus, the etch stoplayer may be exposed in this region. A nonmagnetic gap layer, such as Ruis deposited after removal of the mask. Another portion of theintermediate layer on the opposite side of the main pole may be removed.A second nonmagnetic layer may be deposited in at least the side shieldregion. The second nonmagnetic layer may also be Ru. The first andsecond nonmagnetic layers may form the asymmetric gap on the first sideand top of the main pole. The second nonmagnetic layer may form theasymmetric gap on the second side of the main pole. The top of theasymmetric gap extends closer to the top of the main pole on the firstside than on the second side. The bottom of the asymmetric gap may be onthe etch stop layer on both sides of the main pole. The asymmetric gapis also thicker on the first side than on the second side.

The asymmetric shield(s) are provided in the shield region, via step110. Step 110 may include plating or otherwise providing the material(s)for the side shields. Because the gap is asymmetric, the bottom of theside shields extend different distances along the sides of the main poleon the first side than on the second side. The asymmetric shieldterminates on top of the asymmetric gap. Thus, the asymmetric sideshield extends closer to the bottom of the main pole on the second sidethan on the first side. In some embodiments, the asymmetric shieldterminates between the top and bottom of the main pole on both sides ofthe pole. Thus, the asymmetric shield(s) may be termed asymmetric halfside shields. Note, however, that the asymmetric shields need not extendprecisely halfway down between the top and bottom of the main pole oneither side of the main pole. Instead, the asymmetric side shields mayterminate somewhere between the top and bottom of the main pole. In someembodiments, the asymmetric shield may be configured such that theasymmetric shield terminates at or above the top of the main pole on thefirst side.

Using the method 100, a magnetic transducer having improved performancemay be fabricated. A shingle writer may not need to have side shield(s)which extend to the bottom of the main pole. Thus, the method 100 mayprovide a main pole that may be used in shingle recording. Thus, thebenefits of shingle recording may be exploited. The location of thebottom of the asymmetric shields may be set by the thicknesses of thefirst and second gap layers as well as the location of the etch stoplayer. Thus, the side shield geometry may be tailored.

FIGS. 3A, 3B and 3C depict various views of a transducer 200 fabricatedusing the method 100. FIG. 3A depicts a side view of the disk drive.FIGS. 3B and 3C depict ABS and apex (side/cross-sectional) views of thetransducer 200. For clarity, FIGS. 3A-3C are not to scale. Forsimplicity not all portions of the disk drive and transducer 200 areshown. In addition, although the disk drive and transducer 200 aredepicted in the context of particular components other and/or differentcomponents may be used. For example, circuitry used to drive and controlvarious portions of the disk drive is not shown. For simplicity, onlysingle components are shown. However, multiples of each componentsand/or their sub-components, might be used. The disk drive 200 may be aperpendicular magnetic recording (PMR) disk drive. However, in otherembodiments, the disk drive 200 may be configured for other types ofmagnetic recording included but not limited to heat assisted magneticrecording (HAMR).

The disk drive includes a media 202, and a slider 204 on which atransducer 200 have been fabricated. Although not shown, the slider 204and thus the transducer 200 are generally attached to a suspension. Ingeneral, the slider 204 includes the write transducer 200 and a readtransducer (not shown). However, for clarity, only the write transducer200 is shown.

The transducer 200 includes an underlayer 206, an intermediate layer208, a main pole 210, coil(s) 220, asymmetric gap 230 and asymmetricshields 240. The underlayer 206 may include a bottom (or leading edge)shield. The coil(s) 220 are used to energize the main pole 210. Twoturns are depicted in FIG. 3A. Another number of turns may, however, beused. Note that only a portion of the coil(s) 210 may be shown in FIG.3A. If, for example, the coil(s) 220 is a spiral, or pancake, coil, thenadditional portions of the coil(s) 220 may be located further from theABS. Further, additional coils may also be used.

The intermediate layer 208 may include one or more sublayers as well asan etch stop layer. However, one or more of the sublayers may have beenremoved for formation of the asymmetric gap 230 and asymmetric shields240. Further, the intermediate layer may also include different layersin regions recessed from the ABS.

The main pole 210 is shown as having a top wider than the bottom. Themain pole 210 thus includes sidewalls having sidewall angles that aregreater than or equal to zero. In an embodiment, these sidewall anglesdiffer at different distances from the ABS. In some embodiments, thesidewall angles at the ABS are at least three degrees and not more thanfifteen degrees. In other embodiments, other geometries may be used. Forexample, the top may be the same size as or smaller than the bottom. Thesidewall angles may vary in another manner including, but not limitedto, remaining substantially constant. The main pole 210 may be beingconformal with the trench in the intermediate layer 208. In otherembodiments, however, at least a portion of the main pole 210 may not beconformal with the sides of the trench. In some embodiments, the mainpole 210 may have leading surface bevel 212 and/or a trailing surfacebevel 214, as shown in FIG. 3C.

As can be seen in FIG. 3B, the gap 230 is asymmetric. Thus, the gap onone side of the pole 210 is larger than the part of the gap on the otherside of the main pole 210. In addition, one side of the gap 230terminates further from the bottom of the main pole 210 than the other.

The asymmetric shields 240 are shown as including a trailing shieldportion and half side shield portions. In other embodiments, thetrailing shield portion may be omitted. This is denoted by a dotted linein FIG. 3B. Further, because the asymmetric shields 240 extend differentdistances along the sidewalls of the main pole 210, the dashed lines inFIG. 3C indicate the side portions of the asymmetric shields 240 onopposite sides of the pole. The asymmetric shields 240 are also shown ashaving a constant thickness in FIG. 3C. Stated differently, the bottomsof the asymmetric shields 240 are substantially perpendicular to theABS. Thus, the dashed line corresponding to the bottoms of theasymmetric shields 240 are perpendicular to the ABS. In otherembodiments, the geometry of the asymmetric shields 240 may vary. Forexample, the bottom of the asymmetric shields 240 track the trailingedge of the pole such that the shield covers less of the pole furtherfrom the ABS. In other embodiments, the asymmetric shield thickness mayvary. In such embodiments, the bottom of the half shield portion of theshield 240 may be parallel to the leading bevel 212 or the trailingbevel 214 while the top surface is perpendicular to the ABS. Othervariations are also possible. However, note that bottoms of theasymmetric shields reside on the top of the intermediate layer 208 isbetween the top and bottom of the pole 210.

The magnetic transducer 200 in the disk drive may be used in shinglerecording. Thus, the benefits of shingle recording may be achieved. Forexample, higher areal density recording may be performed by a headhaving larger critical dimensions.

FIG. 4 depicts an exemplary embodiment of a method 120 for providing anasymmetric gap for a magnetic recording transducer. For simplicity, somesteps may be omitted, interleaved, performed in another order and/orcombined. The method 120 may be used to fabricate multiple magneticrecording heads at substantially the same time. The method 120 may alsobe used to fabricate other magnetic recording transducers. The method120 is also described in the context of particular layers. A particularlayer may include multiple materials and/or multiple sub-layers. Themethod 120 also may start after formation of other portions of themagnetic recording transducer. For example, the method 120 may startafter at least a portion of the pole has been fabricated.

A portion of the intermediate layer adjacent to one side of the pole isremoved, via step 122. In some embodiments, step 122 includes providinga mask that covers the pole and another portion of the intermediatelayer along the second, opposite side of the pole. The portion of theintermediate layer may be removed via a wet etch or, in someembodiments, another process such as an RIE. The etch terminates at theetch stop layer. Thus, the second sublayer along the first side of thepole may be removed. The mask may then be removed.

A first nonmagnetic layer is then provided, via step 124. Step 124 mayinclude depositing a Ru layer, for example via chemical vapordeposition, sputtering or another method. In some embodiments, the firstnonmagnetic layer extends across the top of the pole. In otherembodiments, the first nonmagnetic layer is only on the first side ofthe pole. For example, the layer may be provided before removal or themask or the portion of the layer on the top of the pole may be removed.A portion of the first nonmagnetic layer may also reside on the etchstop layer. In some embodiments, step 124 may include refilling theregion adjacent to the first side of the main pole with a nonmagneticmaterial, such as aluminum oxide. Such a refill step may be used toprovide a more flat topography for subsequent steps.

A portion of the intermediate layer adjacent to the second side of themain pole is removed, via step 126. Step 126 may be performed in ananalogous manner to step 122. Thus, the etch stop layer may be exposedalong the second side of the main pole. In some embodiments, the top ofthe first nonmagnetic layer is exposed along the first side of the mainpole.

A second nonmagnetic layer is provided, via step 128. Step 128 may beanalogous to step 124. For example, a Ru layer may be deposited. In someembodiments, the first and second nonmagnetic layers have differentthicknesses. For example, the first nonmagnetic layer may be thickerthan the second nonmagnetic layer. In other embodiments, the thicknessesmay be the same. Fabrication of the magnetic transducer may then becompleted.

FIG. 5 depicts an ABS view of a transducer 200′ having an asymmetric gapfabricated using the method 120. For clarity, FIG. 5 is not to scale.For simplicity not all portions of the transducer 200′ are shown.Although the transducer 200′ is depicted in the context of particularcomponents, other and/or different components may be used. For example,circuitry used to drive and control various portions of the transduceris not shown. For simplicity, only single components are shown. However,multiples of each components and/or their sub-components, might be used.The transducer 200′ may be a PMR transducer. However, in otherembodiments, the transducer 200′ may be configured for other types ofmagnetic recording included but not limited to HAMR.

The transducer 200′ is analogous to the transducer 200 and disk drivedepicted in FIGS. 3A-3C. Consequently, analogous components have similarlabels. For example, the transducer 200′ includes an underlayer 206,intermediate layer 208, pole 210′, gap 230′ and shield 240′ analogous tothe underlayer 206, intermediate layer 208, pole 210, gap 230 and shield240 of FIGS. 3A-3D.

As can be seen in FIG. 5, the asymmetric gap 230′ includes twononmagnetic layers 232 and 234. The magnetic layer 232 is only on thefirst (right) side of the main pole 210′. The second nonmagnetic layer234 covers both sides and the top of the main pole 210′. Thus, the firstnonmagnetic layer 232 may be provided in step 124, while the secondnonmagnetic layer 234 may be provided in step 128. In other embodiments,the first nonmagnetic layer may cover the top and both sides of the mainpole 210 while the second nonmagnetic layer 234 may cover only one sideof the main pole. In addition, the second nonmagnetic layer 234 thatalso forms the top, write gap is depicted as thinner than the firstnonmagnetic layer 232. However, in other embodiments, the relationshipbetween the thicknesses of the layers 232 and 234 may be different. Theshield 240′ is also asymmetric. The portion of the shield 240′ on thefirst side of the main pole 210′ terminates closer to the top and isfurther from the main pole 210′.

The magnetic transducer 200′ in the disk drive may be used in shinglerecording. Thus, the benefits of shingle recording may be achieved. Forexample, higher areal density recording may be performed by a headhaving larger critical dimensions.

FIG. 6 depicts an exemplary embodiment of a method 150 for providing apole for a magnetic recording transducer having asymmetric side gap andshield. For simplicity, some steps may be omitted, interleaved,performed in another order and/or combined. The method 150 is alsodescribed in the context of providing a magnetic recording transducer250 depicted in FIGS. 7-21 depict ABS views of an exemplary embodimentof a transducer 250 during fabrication using the method 150. The method150 may be used to fabricate multiple magnetic recording heads atsubstantially the same time. The method 150 may also be used tofabricate other magnetic recording transducers. The method 150 is alsodescribed in the context of particular layers. A particular layer mayinclude multiple materials and/or multiple sub-layers. The method 150also may start after formation of other portions of the magneticrecording transducer. For example, the method 150 may start after a readtransducer, return pole/shield and/or other structure have beenfabricated.

The material(s) for the first sublayer are full-film deposited, via step152. In some embodiments, step 152 includes full-film depositingaluminum oxide. The materials for the etch stop layer are provided, viastep 154. Step 154 may include full-film depositing silicon dioxide oranother material that is resistant to an aluminum oxide wet etch. Thematerial(s) for the second sublayer are provided, via step 156. Step 156may include full-film depositing aluminum oxide on the silicon oxidelayer. In addition, steps 152, 154, and 156 may be carried out so thatthe structure including two sublayers separated by the etch stop layerare only in the shield region. FIG. 7 depicts an ABS view of thetransducer 250 after step 156 has been performed. Thus, the firstsublayer 262 has been provided on the underlayer 252. The etch stoplayer 264 has been deposited on the first sublayer 262. The secondsublayer 266 has been provided on the etch stop layer 264. Thus, thefirst sublayer 262 and second sublayer 266 may be aluminum oxide whilethe etch stop layer 264 may be silicon oxide. Other materials may beused, but the first and second sublayers are generally desired to beremovable using the same etch. The etch stop layer 264 is desired to beresistant to at least some etches of the layer 262 and 266, butremovable using other etches that are the same as for the layers 262 and266. For example, a particular wet etch that would remove the firstsublayer 262 and the second sublayer 266 would not remove the etch stoplayer 254. However, other etches, such as a chlorine based or fluorinebased RIE may remove layers 262, 264 and 266. The layers 262, 264 and266 form at least part of the intermediate layer 260. The totalthickness of the intermediate layer 260 may be at least that desired forthe main pole. The etch stop layer 264 is desired to be thin, forexample eight to twelve nanometers. In some embodiments, the etch stoplayer 264 is nominally ten nanometers thick. The thicknesses of thelayers 262, 264 and 266 may be designed such that the asymmetric gapresides on the top of the etch stop layer 264 at the desired height.Also shown is underlayer 252. The underlayer 252 may include twosublayers. A portion of the underlayer 252 at and near the ABS may be aNiFe layer used as a leading shield, while a portion of the underlayerrecessed from the ABS may be a Ru layer. However, in other embodiments,other configurations, including other material(s) may be used.

A trench is formed in the intermediate layer, via step 158. Step 158 mayinclude multiple substeps. For example, a mask including an aperturethat corresponds to a trench may be provided on the intermediate layer260. This may be accomplished using a photoresist line mask. Forexample, first and second hard mask layers, such as Ta and Ru, may befull film deposited. The Ta mask layer and the Ru mask layer may each benominally fifty nanometers thick. A photoresist mask having a linecorresponding to the region of the pole near the ABS is then fabricatedon the first and second hard mask layers. A third hard mask layer, suchas Ta, may be provided on the first and second hard mask layers and thephotoresist mask. This hard mask layer may be a Ta layer that isnominally twenty nanometer thick. The photoresist mask is then removed.The location of the photoresist mask forms the location of the aperturein the hard mask layers. The photoresist mask removal may be carried outby side milling the photoresist mask to remove the third hard masklayer, then performing a lift off. A trench is formed in region of theintermediate layer 260 that is exposed by the aperture in the hard masklayers. Step 166 may include performing an aluminum oxide RIE (or otherRIE(s) appropriate for the layers 262, 264 and 266). This RIE may removethe hard mask layers under the aperture in the third hard mask layer orthese hard mask layers may be removed in another manner. In someembodiments, multiple RIEs are used to obtain the desired trench profilefor various regions of the transducer 250. For example, fluorine-basedand/or chlorine-based RIE(s) may be performed. FIG. 8 depicts an ABSview of the transducer 250 after step 158 has been performed. Thus, atrench 277 has been formed in layers 262′, 264′ and 266′ (inintermediate layer 260′). In the embodiment shown, the bottom of thetrench 277 does not reach the underlayer 252 at the ABS. Thus, aperturesare formed in layers 264′ and 266′, but a groove formed in at least partof the layer 262′. However, the trench 277 may be deeper at otherregions, such as in the yoke region. Thus, the pole being formed mayhave a leading edge bevel. In addition, the trench 277 has a triangularprofile at the ABS. In other embodiments, the bottom of the trench 277has a flat surface and, therefore, a trapezoidal shape at the ABS. Thetrench 277 resides below an aperture in the mask 270. The mask 270includes layers 272 and 274. In the embodiment shown, a third hard masklayer may have been removed during formation of the trench 277. In otherembodiments, other masks 270 may be used.

Seed layer(s) that are resistant to an etch of the intermediate layer260 is deposited in the trench, via step 160. In some embodiments, thisseed layer may serve as at least part of the gap. The seed layer mayinclude material(s) such as Ru deposited using methods such as chemicalvapor deposition. In other embodiments, a magnetic seed layer may beused in lieu of or in addition to a nonmagnetic seed layer.

The material(s) for the main pole may then be provided, via step 162.Step 162 includes depositing high saturation magnetization magneticmaterial(s), for example via electroplating. In some embodiments, thepole materials provided in step 162 fills the trench 277. However, inother embodiments, the pole may occupy only a portion of the trench.FIG. 9 depicts an ABS view of the transducer 250 after a step 162 hasbeen performed. Thus, the seed layer 279 and pole materials 280 havebeen provided. A leading bevel may be naturally formed in the magneticpole to the shape of the trench 277 and the deposition techniques used.

A planarization, such as a chemical mechanical planarization (CMP) mayalso be performed, via step 164. In some embodiments, a trailing edge(top) bevel may be formed at this time. In other embodiments, however,the trailing bevel may be formed layer. A mill may also be used toremove the mask 270. FIG. 10 depicts an ABS view of the transducer 250after step 164 has been completed. Thus, the portion of the main polematerials outside of the trench has been removed, forming main pole 280.

A portion of the intermediate layer 260 adjacent to the first side ofthe main pole 280 may be removed, via step 166. In particular, a portionof the second sublayer adjacent to the first side of the main pole 280may be removed in at least the region in which the shields are to beformed. Step 166 includes providing a mask that covers the main pole 280and the second sublayer on the second side of the main pole 280. In someembodiments, the removal of the second sublayer may be performed using awet etch, such as an aluminum oxide wet etch. After the etch, the maskmay be removed. FIG. 11 depicts the transducer 250 during step 166.Thus, the photoresist mask 282 and hard mask 281 are shown covering themain pole 280 and portion of the second sublayer 266″ on the oppositeside of the main pole 280. The second sublayer has been removed from thefirst side of the main pole 280. Thus, the remaining intermediate layer260″ includes the first sublayer 262′, the etch stop layer 264′ and thesecond sublayer 266″. The seed layer 279, etch stop layer 264′ and masks281 and 282 are barriers against the etch used in step 166. FIG. 12depicts the transducer after step 166 has been performed. Thus, themasks 281 and 282 have been removed.

A first nonmagnetic layer for the asymmetric gap is provided, via step168. Step 168 includes depositing a Ru layer, for example via chemicalvapor deposition. FIG. 13 depicts and ABS view of the transducer afterstep 168 has been performed. Thus, nonmagnetic layer 292 is shown. Thus,on the first side of the main pole 280, the gap would be formed by atleast the seed layer 279 and the nonmagnetic layer 292.

The region above the portion of the first nonmagnetic layer 292 that islower than the top of the pole 280 is desired to be refilled. Thus, asacrificial layer is provided, via step 170. Step 170 may includedepositing an aluminum oxide layer and then planarizing the layer. FIG.14 depicts an ABS view of the transducer 250 after the deposition ofsacrificial layer 293. Step 170 may be completed by the planarization,which exposes the top of the first nonmagnetic layer 292 on top of themain pole 280. FIG. 15 depicts an ABS view of the transducer 250 afterstep 170 is completed. Thus, the portion of the sacrificial layer 293′on the first side of the main pole remains.

A trailing bevel may optionally be provided in step 172. Step 172 mayinclude removing the portion of the first nonmagnetic layer 292 on topof the main pole 280, for example via an ion mill. A mask the coverspart of the main pole 280 recessed from the ABS but leaves the portionof the main pole near the ABS uncovered may then be formed. For example,a Ru layer may be full film deposited, then patterned using aphotoresist mask that is recessed from the ABS. An ion mill may then beperformed. Because of shadowing due to the masks, the top of the mainpole 280 may be removed such that the top of the main pole 280 is at anonzero angle from a direction perpendicular to the ABS. Other methodscould also be used to form the trailing bevel. FIG. 16 depicts an ABSview of the transducer 250 after step 172 has been completed. Thus, aportion of the first nonmagnetic layer 292′, refill 293″ and secondsublayer 266″ remains. In addition, the pole 280 is shorter at the ABSthan previously.

The portion of the second sublayer 266″ that is adjacent to the secondside of the main pole 280 is removed in at least the region in which theshields are to be formed, via step 174. Also in step 174, the refill293′ may be removed in at least the region in which the shields are tobe formed. Step 174 may include multiple substeps. For example, a maskthat covers the main pole 280 but uncovers portions of the intermediatelayer 260′ and refill 293′ is provided. FIG. 17 depicts an ABS view ofthe transducer 250 after the mask has been provided. Thus, a nonmagneticlayer 294 and a resist mask 295 are shown. An etch that removes thedesired portions of layers 266″ and 293′ is performed. For example, analuminum oxide wet etch may be used. In other embodiments multipleetches may be performed to remove the desired portions of layers 266″and 293′. FIG. 18 depicts an ABS view of the transducer 250 after thiswet etch has been carried out. Thus, the top of the etch stop layer 264′is exposed on the second side of the main pole 280, while the top of thefirst nonmagnetic layer 292′ is exposed on the first side of the mainpole 280. The mask layers 294 and 295 may then be removed. FIG. 19depicts an ABS view of the transducer 250 after step 174 is completed.Thus, the portions of layers 264′ (on the second side of the main pole280), 292′ (on the first side of the main pole) and 279 (at the edges ofthe main pole 280) as well as the main pole 280 are exposed.

A second nonmagnetic layer that is to form part of the asymmetric gap isdeposited, via step 176. Step 176 may include depositing a nonmagneticlayer using chemical vapor deposition, sputtering, plating or anothermethod. FIG. 20 depicts an ABS view of the transducer 250 after step 176is carried out. Thus, a nonmagnetic layer 296 is deposited. Thenonmagnetic layer 296 may also form all or part of the write gap as itresides on the trailing surface of the main pole 280. The asymmetric gap298 may be considered to be formed by layers 292′, 296 and 279.

The asymmetric shield(s) may be provided, via step 178. Step 178 mayinclude depositing a seed layer as well as the material(s) for theshields. For example, a seed layer may be deposited, followed byelectroplating of a magnetic material such as NiFe. In some embodiments,the asymmetric shields are part of a wraparound shield. Thus, step 178may also include providing a wraparound shield. If the layer 296 is notto form the write gap, then a write gap layer may also be provided. FIG.21 depicts an ABS view of the transducer 250 after step 178 has beenperformed. Thus, the asymmetric shield 300 is shown. As can be seen inFIG. 21, the shield 300 terminates closer to the trailing surface of themain pole 280 on the first side than on the second side of the main pole280. This is because of the presence of the asymmetric gap 298. Theasymmetric shield 300 also includes a trailing shield portion above thetop/trailing surface of the main pole 280. Thus, the asymmetric shield300 may be considered a wraparound shield. In other embodiments, thetrailing portion of the shield 300 might be removed.

Using the method 150, the transducer 250 including shield 300 may beprovided. Thus, the benefits of shingle recording may be achieved. Forexample, higher areal density recording may be performed by a headhaving larger critical dimensions.

We claim:
 1. A magnetic transducer having an air-bearing surface (ABS)comprising: an intermediate layer having a trench therein; a main pole,a portion of the main pole residing in the trench, the main pole havinga bottom, a top wider than the bottom, a first side and a second sideopposite to the first side; an asymmetric gap having a first portion ofthe asymmetric gap along the first side of the main pole, a secondportion of the asymmetric gap along the second side of the main pole,and a third portion of the asymmetric gap along the top of the mainpole, the asymmetric gap terminating between the top and the bottom ofthe main pole, the first portion of the asymmetric gap terminatingcloser to the top of the main pole than the second portion of theasymmetric gap, the first portion of the asymmetric gap having a firstthickness, the second portion of the asymmetric gap having a secondthickness, the second thickness being different from the firstthickness; and an asymmetric shield on the asymmetric gap, theasymmetric shield including a half side shield, a bottom of the halfside shield being between the top and the bottom of the main pole andterminating on the asymmetric gap.
 2. The magnetic recording transducerof claim 1 further comprising: a leading shield.
 3. The magneticrecording transducer of claim 1 wherein the second thickness is lessthan the first thickness.
 4. The magnetic recording transducer of claim1 wherein the intermediate layer further includes: an etch stop layer, afirst portion of the etch stop layer residing under the first portion ofthe asymmetric gap, a second portion of the etch stop layer residingunder the second portion of the asymmetric gap.
 5. The magneticrecording transducer of claim 1 wherein the asymmetric gap furtherincludes a third portion and a fourth portion, the third portionadjoining the first portion and extending in a cross track direction,the fourth portion adjoining the second portion and extending in thecross track direction.
 6. The magnetic recording transducer of claim 5wherein the asymmetric shield includes a trailing shield, the trailingshield is magnetically coupled with the half side shield such that thetrailing shield and the half side shield form a wraparound shield.